Irvine, Calif.-According to new research at the University of California Irvine, turf grass lawns, which help remove carbon dioxide from the atmosphere through photosynthesis and store it as organic carbon in soil, don’t help much to reduce greenhouse gases. Researchers concluded that lawn management practices from producing the fertilizer, mowing, and leaf blowing offset the stored carbon by a factor of four. “Lawns look great – they’re nice and green and healthy, and they’re photosynthesizing a lot of organic carbon. But the carbon-storing benefits of lawns are counteracted by fuel consumption,” says Amy Townsend-Small, Earth system science postdoctoral researcher and lead author of the study, which will be forthcoming in the journal Geophysical Research Letters. “It’s impossible for these lawns to be net greenhouse gas sinks because too much fuel is used to maintain them.” Nitrous oxide released from soil after fertilization is a big offender, because NoX is a greenhouse gas that’s 300 times more powerful than carbon dioxide, the Earth’s most problematic climate warmer. Townsend-Small insists that the research results are important to greenhouse gas legislation being negotiated because “we need this kind of carbon accounting to help reduce global warming.” She noted that the current trend is to count the carbon sinks and forget about the greenhouse gas emissions. Researchers evaluated soil samples over time to ascertain carbon storage, and they determined NoX emissions by sampling air above the turf in four parks near Irvine containing two types of turf: ornamental lawns in picnic areas that are largely undisturbed, and soccer and baseball fields that are trampled, replanted, and aerated frequently. Carbon dioxide emissions from fuel consumption, irrigation, and fertilizer production were calculated using information about lawn upkeep from park officials and contractors. The study showed that nitrous oxide emissions from lawns were comparable to those found in agricultural farms.
Transparency Across the Fertilizer Value-Chain